Miroljub Barać, Nevena Barać, Irzada Taljić
et al.
Diabetes mellitus, particularly type 2 diabetes (T2D), is one of the most prevalent metabolic disorders worldwide, strongly influenced by lifestyle and nutritional factors. Current dietary recommendations emphasize the importance of carbohydrate quality and food matrix effects in modulating glycaemic control and insulin sensitivity. Lactose, the principal disaccharide in milk, is frequently overlooked in the context of diabetes research, as most attention has been focused on other dietary sugars such as glucose, sucrose, and fructose. However, lactose displays a relatively low glycaemic index compared to other carbohydrates and is hydrolysed into glucose and galactose, the latter showing potential antioxidative and anti-inflammatory effects. Moreover, a growing body of evidence suggests that dairy intake is associated with a reduced risk of type 2 diabetes, with fermented dairy products, such as yogurt and kefir, consistently showing the most protective associations. Recent studies have further highlighted the role of genetic variation in lactase persistence and non-persistence, pointing to the potential influence of gut microbiota and lactose fermentation products on glucose homeostasis. The aim of this review is to provide an overview of current evidence linking lactose metabolism and dairy consumption to the risk, regulation, and management of type 2 diabetes.
Falah Awwad, Ghassan Al-Sumaidaee, Aya Eltayeb
et al.
ABSTRACT: Fermented dairy products are increasingly valued not only for their nutritional content but also for their potential health-promoting properties. However, assessing these functional benefits often requires time-consuming chemical assays that limit scalability. In this study, we investigated whether deep learning (DL) could offer a faster, more efficient alternative. Using liquid chromatography (LC)-MS quadrupole time-of-flight metabolomics, we analyzed 18 fermented milk samples (derived from camel and bovine milk fermented with different bacterial strains) and measured their bioactivity across 9 in vitro assays, including antioxidant capacity (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl), enzyme inhibition (angiotensin-converting enzyme, degree of hydrolysis), and anticancer activity (HT-29, MDAMB). To address the challenge of limited sample size, we implemented a robust preprocessing pipeline including outlier detection, robust scaling, and data augmentation techniques. We trained a one-dimensional convolutional neural network (1D-CNN; DL) architecture with regularization strategies to predict these bioactivity scores from preprocessed LC-MS data. The model achieved strong performance with a mean absolute error of 0.548 ± 0.089 across all outputs through 3-fold cross-validation, demonstrating effective generalization despite the small dataset. Principal component analysis revealed biologically meaningful structure in the metabolomic data, distinguishing samples by milk type and fermentation condition. Together, these results demonstrate that DL with appropriate regularization and data augmentation can accurately predict the functional bioactivity of fermented milk products from metabolomic signatures, offering a promising path toward scalable, DL-assisted screening in functional food development, even with limited training data.
ABSTRACT: Heavy metal contamination is a serious food safety issue. Herein, we report a rapid, multiplexed, and naked-eye-readable method for detecting heavy metal pollution in food samples, including milk, using an inexpensive colorimetric paper. We leverage the urease catalysis reaction to amplify the presence of the heavy metal ions Hg2+ and Pb2+ by exploiting their strong inhibitory effect on urease. Integrating with a paper-folding strategy, the visual assay realizes rapid detection of over 10 samples within 5 min. It allowed detection of Hg2+ as low as 0.1 nM and Pb2+ as low as 2 μM. Results can be visually interpreted with the naked eye or a smartphone, making it practical for on-site testing and ensuring the safety of dairy products against metal contamination.
Rudy Sykora, Bishal Barman, Hussein M.H. Mohamed
et al.
ABSTRACT: Bovine milk is a nutritionally rich fluid containing bioactive proteins that support immune function and growth. Traditional thermal pasteurization (72°C for >15 s) ensures microbial safety but degrades heat-sensitive proteins. High-pressure processing (HPP) offers a nonthermal alternative for microbial reduction, yet its effect on protein structure, particularly under applications of multiple pressure cycles, remains underexplored. This study aimed to evaluate the effectiveness of single- and dual-cycle HPP treatments for bacterial inactivation and protein preservation in whole bovine milk and to compare these results with the industry standard—HTST processing. Raw bovine milk samples were inoculated with vegetative pathogens (Listeria monocytogenes, Staphylococcus aureus) or spores (Bacillus cereus, Bacillus subtilis) and treated with varying HPP conditions (350–600 MPa; 4–12 min, at 30°C, for single or dual cycles). Microbial reduction was assessed by standard plate count. Whey protein retention (lactoferrin [LF], IgA, IgG, IgM) was quantified using ELISA and compared with HTST and raw milk controls. Dual-cycle HPP treatments significantly enhanced bacterial reduction compared with single-cycle time equivalents for S. aureus and B. subtilis, but not for L. monocytogenes or B. cereus. Treatments for S. aureus demonstrated 0.6 to 2.5 log reduction increases from single to dual cycles at pressures of 350 to 600 MPa. Although no tested treatments achieved >5-log reductions in sporulated B. subtilis, dual-cycles increased reductions by 1.2 log compared with single-cycle time equivalents. Several conditions achieved >5-log reductions for vegetative pathogens, including 600 MPa, 12 min, single cycle; 550 and 600 MPa, 4 min dual cycle, and 550 and 600 MPa, 6 min, dual-cycle. However, all HPP treatments led to substantial degradation of immunological proteins, particularly LF (53%–84% reduction), IgA (86%–95% reduction), and IgM (81%–98% reduction), with protein retention decreasing as pressure and cycle time increased. High-temperature, short-time processing preserved higher levels of native protein structure across all treatments.
C. Heffernan, T.F. O'Callaghan, R. Fitzgerald
et al.
ABSTRACT: The objective of this experiment was to investigate the effect of concentrate supplement level and type on the milk fat production of grazing dairy cows in early to mid-lactation during a high-risk period for reduced milk fat synthesis. Eighty Holstein Friesian dairy cows averaging (mean ± SD) 55 ± 14 DIM were blocked based on their pre-experimental milk production and parity and randomly assigned to 1 of 5 dietary treatments: a pasture-only (P) control supplemented with 0.27 kg of DM/cow per day of a mineral and vitamin pack (P0); P supplemented with 2 kg of DM/cow per day of an industry-standard concentrate (P2); P supplemented with 4 kg of DM/cow per day of an industry-standard concentrate (P4); P supplemented with 4 kg of DM/cow per day of a concentrate containing 10% sodium hydroxide-treated straw (P4S); and P supplemented with 4 kg of DM/cow per day of a concentrate containing 5% calcium salts of fatty acids (P4F). The experiment consisted of an initial 2-wk covariate period, 1 wk of diet acclimatization, and a 12-wk period of data collection. Concentrate supplement level and type had no effect on milk fat concentration. Increasing the concentrate supplementation level linearly increased milk yield, ECM yield, fat yield, protein yield, lactose yield, and milk solids yield. Cows fed P4F had greater milk yield and lactose yield but lower milk protein concentration compared with cows fed P4 and P4S. Compared with the P4S diet, cows fed the P4F diet had greater milk fat yield and tended to produce greater milk solids yield. Cows fed P4F had lower proportions of de novo and mixed fatty acids (FA), as well as greater proportions of preformed FA compared with cows fed P4 and P4S. Cows fed P2 and P4 increased DM and OM intake compared with cows fed P0; however, cows fed P2 and P4 were similar. The total FA intake of cows fed P4 was greatest (400 g/d), cows fed P2 was intermediate (370 g/d), and cows fed P0 was lowest (330 g/d). Changing the concentrate type had no effect on the intakes of total DM, pasture DM, and OM. These results suggest that, although concentrate level and type can affect milk fat yield, they do not affect the milk fat concentration of grazing dairy cows within the conditions investigated in this experiment. Further research is required to determine the nutritional and non-nutritional factors responsible for reducing milk fat concentration in pasture-based systems during the high-risk period.
ABSTRACT: The size of fat globules in ruminant milk to some extent affects the nutritional quality of dairy products and plays potential roles in infant and adult health. Lipid droplets (LD) in mammary epithelial cells are the precursors of milk fat globules (MFG). However, it is unclear what happens to proteins during the transformation process from LD to MFG, and little is known about the regulation of LD diameter in vivo. In this study, 12 mid-lactation Saanen dairy goats were randomly divided into 2 groups: a control group fed a basal diet and an experimental group fed a basal diet supplemented with CLA at 90 g/d. Goat milk was collected for analysis of composition and MFG size. Mammary gland tissue was collected for analysis of LD diameter and proteins. The size of MFG was found to depend on LD diameter in the mammary glands of dairy goats. The regression equations for MFG size (Y) and LD diameter (x) were YD[3,2] = 1.8776x − 1.1984 (R2 = 0.7765) and YD[4,3] = 2.4898x − 0.4453 (R2 = 0.7693), respectively. Proteomic analysis revealed increased expression of proteins associated with lipid droplet autophagy and lipolysis (such as ATG5, ATG7, LDHA, MGL), whereas expression decreased for proteins involved in lipid synthesis (such as PLIN1, FASN, LPL, SCD, APOH). These LD proteins regulated LD diameter through glucose and lipid pathways metabolism, thereby affecting MFG size. Overall, these findings provide the first evidence that LD diameter determines MFG size and highlight the regulatory functions of LD protein in milk fat production.
ABSTRACT: This article summarizes the applications of biosensors and biomimetic sensors in the detection of residues in dairy products. Biosensors use biological molecules, such as enzymes or antibodies, to detect residual substances in dairy products, demonstrating high specificity and sensitivity. Biomimetic sensors, inspired by biosensors, use synthetic materials to mimic biological sensing mechanisms, enhancing stability and reproducibility. Both sensor types have achieved notable success in detecting pesticide residues, veterinary drugs, bacteria, and other contaminants in dairy products. The applications of biological and biomimetic sensors not only improve the efficiency of residue detection in dairy products but also have the potential to reduce the time and cost of traditional methods. Their specificity and high sensitivity make them powerful tools in the dairy industry, thus contributing to ensuring the quality and safety of dairy products and meeting the growing consumer demands for health and food safety.
Alexander Lucquin, Harry K. Robson, E. Oras
et al.
Significance How prehistoric farming became established in Northern Europe, a region that supported dense populations of hunter-gatherer-fishers, has concerned archaeologists for over a century. Through analysis of the organic residues recovered from over 1,000 vessels dating across the transition to farming, we found unexpected consistency in the use of aquatic foods at odds with prevailing narrative of large-scale demographic and economic change. We argue that the ability of farming groups to adapt to their environment by learning hunter-gatherer-fisher practices, combined with dairying, was key to their northerly expansion. We also provide evidence of dairy use by hunter-gatherers which we attribute to long-distance exchange with farmers, implying a much greater degree of interaction and cooperation than previously described.
S. Wilkin, A. R. Ventresca Miller, W. Taylor
et al.
Dairy pastoralism is integral to contemporary and past lifeways on the eastern Eurasian steppe, facilitating survival in agriculturally challenging environments. While previous research has indicated that ruminant dairy pastoralism was practiced in the region by circa 1300 bc, the origin, extent and diversity of this custom remain poorly understood. Here, we analyse ancient proteins from human dental calculus recovered from geographically diverse locations across Mongolia and spanning 5,000 years. We present the earliest evidence for dairy consumption on the eastern Eurasian steppe by circa 3000 bc and the later emergence of horse milking at circa 1200 bc, concurrent with the first evidence for horse riding. We argue that ruminant dairying contributed to the demographic success of Bronze Age Mongolian populations and that the origins of traditional horse dairy products in eastern Eurasia are closely tied to the regional emergence of mounted herding societies during the late second millennium bc. Ancient proteins in human dental calculus from sites across Mongolia spanning 5,000 years suggest dairy consumption on the eastern Eurasian steppe by circa 3000 bc, and the later emergence of horse milking at circa 1200 bc, concurrent with the first evidence for horse riding.
Hussaini Yusuf Ibrahim, Umar Ibrahim, Abdullahi Abubakar Khidir
et al.
The study analyzed farmers' level of adoption and perception of phosphorus based fertilizers for cowpea production in Katsina state, Nigeria. A total of 153 cowpea farmers were sampled using a multi-stage sampling technique. Primary data was utilized in the study. The data was collected using a structured questionnaire by trained enumerators. Descriptive statistics, Kendalls’ coefficient of concordance and acceptability index were employed for data analysis. The results showed that the mean age for cowpea farmers was 41 years. Distribution of the respondents by gender reveals that 85.6% were males and the remaining 14.4% were females. The result of farmers’ perception of phosphorus-based fertilizer used shows a moderate agreement of 0.30 which indicates different perceptions among respondents. The study further revealed that the acceptability index of 6.54% was very alarming because cowpea farmers committed a small portion of their farmland toward adopting the technology. The level of knowledge of the cowpea farmers on phosphorus based fertilizers was very low, leading to a very low level of acceptance of phosphorus fertilizers in the study area. It was recommended that be made available and affordable to the cowpea farmers as this will increase the rate of technology adoption in the study area.
Robert M. Hyde, Martin J. Green, Chris Hudson
et al.
ABSTRACT: Neonatal calves are relatively susceptible to heat loss, and previous research suggests that reduced environmental temperatures are associated with reduced average daily gain (ADG) during the preweaning phase. Current methods of mitigating negative effects of colder environmental conditions include the use of calf jackets and the provision of supplementary heat sources; however, previous research is limited. The aim of this study was to evaluate the effect of calf jackets and 1-kW heat lamps on the growth rates of preweaning calves and evaluate associations between environmental temperature and ADG using a Bayesian approach to incorporate both current and previous data. Seventy-nine calves from a single British dairy farm were randomly allocated at birth to 1 of the following 4 groups: no jacket and no heat lamp, heat lamp but no jacket, jacket but no heat lamp, or both heat lamp and jacket between January and April of 2021. Calves were weighed at both birth and at approximately 21 d of age. Temperature was recorded both inside and outside of the calf building, and in pens both with and without heat lamps using data loggers. To explore the effect of treatment group and environmental temperature on ADG, a fixed effects model was fitted over 1,000 bootstrap samples. The effect of environmental temperature on ADG was further explored within a Bayesian framework that used temperature and ADG data for 484 calves from 16 farms available from a previous trial as prior information. Calves housed under a 1-kW heat lamp had an increased ADG of 0.09 kg/d (95% bootstrap confidence interval: −0.02 to 0.20 kg/d), and no effect of jacket or interactions between jacket and heat lamp were found. A significant positive association was identified between the mean environmental temperature of the calf building and ADG, with a 1°C increase in temperature being associated with a 0.03 kg/d increase in ADG (95% bootstrap confidence interval: 0.01 to 0.04 kg/d). Associations between environmental temperature and ADG were further evaluated within a Bayesian framework, and posterior estimates were 0.014 kg/d of ADG per 1°C increase (95% credible interval: 0.009 to 0.021 kg/d). This study demonstrated that a 1-kW heat lamp was effective in increasing ADG in calves, and no significant effect of calf jacket on ADG was found. A significant, positive effect of increased pen temperature on calf ADG was identified in this study and was reinforced when including prior information from previous research within a Bayesian framework.
ABSTRACT: Free exopolysaccharide (f-EPS) produced by Streptococcus thermophilus improves the texture and functionality of fermented dairy foods. Our previous study showed a major improvement in f-EPS production of Strep. thermophilus 937 by increasing the concentrations of histidine, isoleucine, and glutamate to 15 mM in an optimized chemically defined medium. The aim of this study was to elucidate the effect of His, Ile, and Glu on the growth, f-EPS biosynthesis pathway, and carbohydrate metabolism profiles of Strep. thermophilus 937. The growth kinetics; transcript levels of key genes in the EPS biosynthesis pathway; enzyme activity involved in sugar nucleotide synthesis; concentrations of lactic acid, lactose, and galactose; and extracellular and intracellular pH were analyzed in chemically defined media with different initial histidine, isoleucine, and glutamate concentrations. The results showed that f-EPS production and viable cell counts of Strep. thermophilus 937 increased 2-fold after the concentrations of His, Ile, and Glu were increased. Additionally, increasing the concentrations of His, Ile, and Glu upregulated transcription of EPS biosynthesis genes and increased the activity of key enzymes in sugar nucleotide synthesis. Moreover, the consumption of lactose increased and secretion of galactose decreased, indicating that increasing the concentration of His, Ile, and Glu could enhance f-EPS production by maintaining viable cell counts, promoting sugar nucleotide synthesis, and increasing the transcript levels of the eps gene cluster. Our results provide a better understanding of the effect of AA on EPS biosynthesis in Strep. thermophilus.
ABSTRACT: Although puerperal metritis (PM) is a common infectious disease in dairy cattle, there are currently discrepancies between clinical case definitions within and between available peer-reviewed literature and on-farms practices. The inconsistent use of PM criteria across studies and on-farms practices can result in disparities related to recommendations for treating cows, affecting judicious use of antimicrobials. The objective of this study was to systematically review the peer-reviewed literature for clinical signs used for case definition of PM. The criteria used included local (e.g., vaginal discharge) and systemic clinical signs of infection (e.g., fever, drop in milk). The Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews protocols were used to screen commonly used databases. Following this protocol, one reviewer screened title and abstract for eligibility (n = 2,096), followed by full-text screening of selected articles (n = 396) by 2 reviewers to confirm eligible articles (n = 174). The most frequently cited reference article (37.5%) for the definition of PM was published in 2006, followed by articles published between 1998 and 2009 (13%). In 40.2% of articles, no reference was provided for definition of PM; vaginal discharge was described in terms of color, odor, and viscosity when related to the PM definition. Terms used for description of vaginal discharge color were red-brown (61.4%), red (5.1%), brown (8.6%), chocolate (4%), white (1.7%), yellow (0.5%), pink (5.7%), or gray (0.5%); vaginal discharge color was not reported in 24.1% articles. The vaginal discharge odor was described as fetid (75.8%), putrid (5.1%), foul (10.3%), or other (5.7%; e.g., abnormal, malodorous, odoriferous); odor was not mentioned in 7.4% of articles. The vaginal discharge viscosity was described as watery (74.1%), purulent (27%), mucopurulent (8.6%), thin (4%), serous (2.8%), or abnormal (2.3%) and was not mentioned in 11.5% of articles. Fever was included in 59.7% of articles as a criterion for PM diagnosis. The most used rectal temperature threshold was ≥39.5°C (56.8%), followed by ≥39.2°C (2.8%). Approaches used for vaginal discharge evaluation included rectal palpation (37.3%), intravaginal exploration with a gloved hand (18.4%), Metricheck (9.8%), or speculum (5.7%); and in 28.7% of articles, diagnostic tools used were not mentioned. Many of the color and odor vaginal discharge descriptions observed in the literature, used synonymous words to describe the same vaginal discharge sample, highlighting a lack of terminology consensus that could result in disagreements, especially due to the subjective character of these clinical evaluations of vaginal discharge color and odor. Although select consensus articles are available, it is common for studies to disregard a reference when defining PM cases. Furthermore, our findings highlight the need for a robust and clear consensus on criteria and terminology used to diagnose PM.
ABSTRACT: The objectives were to investigate whether supplementation with rumen-protected choline (RPC) during late pregnancy in Holstein cows affects offspring immunity and growth, and whether effects are utero-placental, colostrum dependent, or both. A total of 105 multiparous Holstein cows were assigned randomly to a prepartum diet (1.54 Mcal of NEL/kg of DM, and 15.8% CP) without (control) or with added RPC (12.9 g/d of choline ion). Calves (n = 111) were blocked by sex and assigned randomly to colostrum from control cows or colostrum from RPC cows, resulting in 4 treatments in a 2 × 2 factorial arrangement: (1) calves born and fed colostrum from non-supplemented dams (NN; n = 33); (2) calves from non-supplemented dams and fed colostrum from RPC-fed cows (NC; n = 25); (3) calves from RPC-supplemented dams and colostrum from non-supplemented cows (CN; n = 28); and (4) calves from RPC-supplemented dams and colostrum from RPC-fed cows (CC; n = 25). Growth, intakes, and immunity of females were evaluated up to 56 d of age. Growth and intake of male calves was evaluated up to 35 d of age, and physiological and immune responses to intravenous LPS challenge were evaluated from 21 to 35 d of age. Effects of prenatal and colostrum treatments and interactions between treatments were analyzed using mixed models. Calves fed colostrum from RPC-supplemented dams had a 17.4% increase in apparent efficiency of absorption of IgG compared with calves fed colostrum from control dams (27.4 vs. 23.3%). Incidence of fever in the first 21 d of age tended to be less in females born from RPC-supplemented dams compared with females born from control dams (31 vs. 58%). Prenatal RPC females had increased hematocrit and concentrations of red blood cells, leukocytes, neutrophils, and lymphocytes in blood compared with prenatal females born from control dams. Compared with prenatal control females, prenatal RPC females had greater intake of milk replacer (704 vs. 748 ± 9.9 g/d) and starter (45.4 vs. 60.2 ± 5.9 g/d) during the first 21 d of age. In male calves, mean intake of DM was greater (1,074 vs. 976 ± 45 g/d) after the LPS challenge (0 to 8 d) by calves born from dams fed RPC compared with males born from control dams. Calves born from RPC-fed dams also had lower mean rectal temperature (39.0 vs. 39.2°C) and mean respiration rate (35.6 vs. 39.3 breaths/min) compared with males born from control dams. Moreover, serum concentrations of metabolites (i.e., β-hydroxybutyric acid, fatty acids, and glucose), cytokines (i.e., tumor necrosis factor-α) and acute phase proteins (i.e., serum amyloid A) were consistent with less-severe inflammatory response to LPS in males born from dams fed RPC compared with control. Source of colostrum and interaction between prenatal and colostrum treatments had minimal effects on calf responses to LPS. Overall, maternal RPC supplementation during late gestation suggests a positive effect on immunity, in that colostrum from RPC-fed dams increased efficiency of IgG absorption and maternal supplementation with RPC during late gestation, regardless of colostrum source, attenuated responses to LPS.
ABSTRACT: Studies have shown that β-glucans extracted from the cell wall of cereals, algae, and yeasts have been associated with improved immune function. However, it is unknown whether algae β-glucan supplementation affects the performance, blood metabolites, or cell counts of immune cells in dairy calves. The objective of this randomized clinical trial was to evaluate whether supplementation of β-glucans to milk replacer in dairy calves fed 6 L/d improved growth performance and fecal status and altered the blood metabolite profile. In this trial, we enrolled Holstein calves (n = 34) at birth (body weight 36.38 ± 1.33 kg; mean ± standard deviation) to receive, from 1 d of age, either 2 g/d algae β-glucans mixed into 6 L/d of milk replacer (22.4% crude protein and 16.2% fat) or an unsupplemented milk replacer (control). The calves were blocked in pairs according to birth weight, sex, and date of birth (up to 5 d difference). Calves were housed individually, and calf starter (24.7% crude protein and 13.9% neutral detergent fiber) was offered ad libitum based on orts of the previous day until 56 d of age (end of the trial). Body weight was measured weekly, and health checks and daily fecal consistency were evaluated daily in every calf by the same observer. Calves with 2 consecutive days of loose feces that sifted through bedding were considered diarrhea positive. We used a linear mixed effects model to evaluate the effects of β-glucan supplementation fed during the preweaning period on performance (average daily gain), final weight, feed efficiency (FE), white blood cell count, and selected blood metabolites, repeated by time. A generalized linear mixed effects model was also run to evaluate the likelihood of a diarrhea bout in the first 28 d of life, controlling for the calf as the subject with a logistic distribution. We included age, serum total protein at 48 h, and birth weight as covariates. At 56 d, β-glucan-supplemented calves weighed more than control calves (56.3 vs. 51.5 kg). Treatment had no effect on total starter intake, but there was a treatment by age interaction for FE, with greater FE for β-glucan-supplemented calves in wk 3 and 5 of age. There was only a tendency for average daily gain to be greater in supplemented calves than in control calves for the duration of the study. Furthermore, control calves had 14.66 [95% confidence interval (95% CI): 9.87–21.77] times greater odds of having a diarrheal bout than β-glucan-supplemented calves. Control calves had 12.70 (95% CI: 8.82–18.28) times greater odds of having an additional day with an abnormal fecal score compared with β-glucan-supplemented calves, suggesting that supplementation ameliorated diarrhea severity. We found no association of treatment with concentrations of serum total protein, albumin, creatinine, or glucose during the preweaning period. Our findings suggest that dietary supplementation of 2 g/d of algae β-glucans to milk replacer improved fecal status and may affect growth, as evidenced by a higher weaning weight, compared with control calves. Future studies should explore the effect of algae β-glucans on lower-gut physiology and digestibility in dairy calves.
ABSTRACT: In a randomized complete block design, 40 lactating Holstein cows (average 98 d in milk and 41 kg/d of milk yield) were randomly assigned to 1 of 4 diets: (1) containing soybean meal as the major protein supplement (CON diet); (2) CON diet with high-protein dried corn distillers grains at 20% on a dry matter (DM) basis by replacing mainly soybean meal (DG diet); (3) DG diet except that high-protein dried corn distillers grains with yeast bodies (extracted after corn ethanol production) was used (DGY diet); or (4) DG diet supplemented with sodium bicarbonate and potassium carbonate to elevate the dietary cation and anion difference (DCAD; DG-DCAD diet). The DCAD of CON, DG, DGY, and DG-DCAD were 185, 62, 67, and 187 mEq/kg of DM, respectively. The experiment began with a 10-d covariate period and then cows were fed the experimental diets for 5 wk (2-wk diet adaptation and 3-wk data collection periods). Dry matter intake and milk yield were measured daily, and spot urine and fecal samples were collected in the last week of the experiment to measure nutrient digestibility; N, S, and P utilization and excretion; and in vitro NH3 and H2S emissions from manure. All data were analyzed using the MIXED procedure of SAS (random effect: block; fixed effects: diets, repeated week, and interactions). During data collection, DM intake was not different among treatment groups, but milk yield tended to be lower (42.4 vs. 39.9 kg/d) for DG, DGY, and DG-DCAD versus CON, which could have been caused by decreases in organic matter and neutral detergent fiber digestibility. Milk protein yield tended to be lower (1.33 vs. 1.24 kg/d) for DG, DGY, and DG-DCAD versus CON. Milk fat yield was lower (1.26 vs. 1.55 kg/d) for DG and DGY versus CON, but that for DG-DCAD (1.43 kg/d) did not differ from CON. Similarly, energy-corrected milk was lower (38.0 vs. 43.3 kg/d) for cows on DG and DGY versus those on CON, but it did not differ between DG-DCAD (40.7 kg/d) and CON. Urinary and fecal N excretion were greater for DG, DGY, and DG-DCAD compared with CON due to greater dietary crude protein content and N intake. However, NH3 emissions did not differ across treatments. Intakes of dietary P and S were greater for DG, DGY, and DG-DCAD, resulting in greater excretion of those in manure and greater H2S emissions from manure compared with CON. These data suggest that the negative effects of feeding distillers grains on production of lactating cows can be partly explained by a decrease in nutrient digestibility (milk yield) and excessive anion load (milk fat). The milk fat response to DG-DCAD suggests that milk fat depression observed with a diet with high content of distillers grains can be partially alleviated by supplementation of cations. In the current study, we observed no beneficial effects of DG containing yeast bodies.
The aim of this research was to determine the microbiota of commercial kefir, koumiss and homemade kefir samples using metagenomic analysis and compare some probiotic properties of lactic acid bacteria isolated from these beverages and Lactobacillus casei, used in yakult production. One koumiss, 5 commercially available kefir beverages with different brands, and 1 homemade kefir were used as samples. Microbial diversity of kefir and koumiss samples were determined by metagenomic analysis, targeting V1-V2 region of 16S rRNA gene. Streptococcus thermophilus and Lactococcus lactis were detected as dominant in direct DNA isolation from commercially available kefir beverages. Lc. lactis and Leuconostoc mesenteroides were dominant in MRS agars, and Lc. lactis were dominant in M17 agars. In kefir beverages produced by kefir grains, Lb. kefiranofaciens was determined as the dominant bacteria. Lb. kefiri and Enterococcus durans were found dominant in MRS and M17 agars respectively. Lb. kefiranofaciens, Lb. kefiri, and Str. thermophilus were the dominant bacterias of koumiss beverages. Microorganisms isolated from kefir and koumiss beverages were found to exhibit basic probiotic properties, similar to the lactic acid bacteria isolated from yakult. This research presented bacterial microflora and probiotic properties of lactic acid bacteria isolated from kefir and koumiss beverages consumed in Turkey.
David Chapman, Ina Pinxterhuis, Stewart Ledgard
et al.
As the pressure intensifies to reduce nitrogen (N) losses to the environment from pasture-based dairy systems, interest in reducing N-fertiliser inputs and returning to grass–clover mixtures, where more N for pasture growth is supplied by biological N fixation (BNF), have been revived. However, the following question then arises: is BNF fundamentally different from fertiliser N with respect to N losses, especially nitrate-N leaching risk? The present paper addresses this question by reviewing empirical evidence in the context of N-cycling processes and the efficiency of N use for herbage production. Nitrate leaching data from studies comparing different sward treatments at the same level of total N inputs (fertiliser plus BNF) provide no evidence to suggest that leaching differs when N is supplied solely by fixation in mixtures, by fixation plus fertiliser in mixtures, or solely as a fertiliser to grass monoculture. Increasing clover content in mixed grass–clover pastures is likely to increase N leaching due to a lower ratio of soluble sugar and starch to N in herbage than the common companion grass species perennial ryegrass, and, therefore, a higher partitioning of N eaten to urine. Counteracting this effect, mixed grass–clover pastures may offer some potential for increasing N-use efficiency and reducing the whole-farm N surplus compared with grass-dominant pasture receiving high rates of N fertiliser. While there are undeniable benefits for the productivity of dairy systems from maintaining strong grass–clover mixtures, it is the total amount of N entering the system, rather than the form of N (BNF or fertiliser), that influences nitrate leaching rates.